European Environment Eur. Env. 13, 1–18 (2003) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/eet.305 INTEGRATING THE ENVIRONMENT INTO STRATEGIC DECISION-MAKING: CONCEPTUALIZING POLICY SEA William R. Sheate, 1 * Suzan Dagg, 1 Jeremy Richardson, 2 Ralf Aschemann, 3 Juan Palerm 4 and Ulla Steen 5 1 Environmental Policy and Management Group (EPMG), Department of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, University of London, RSM Building, Prince Consort Road, London SW7 2BP, UK 2 Scott Wilson Kirkpatrick and Co Ltd, 71 Victoria Street, London SW1H 0SW, UK 3 Austrian Institute for the Development of Environmental Assessment, Elisabethstrasse 3/3A, 8010 Graz, Austria 4 Entidad Colaboradora de la Administracion (ECA) SA, Quatre Camins 9 – 15, 1oB 08022 Barcelona, Spain 5 Niras Consulting Engineers and Planners, Vestre Havnepromenade 9, 9100 Aalborg, Denmark Strategic environmental assessment (SEA) is seen as an important tool for integrating the environment into decision-making, e.g. at plan and programme levels where it is being used with increasing regularity. At the policy and most strategic decision levels, however, it is less clear how SEA can best be used or what methodologies are appropriate in what are inevitably * Correspondence to: William R. Sheate, Environmental Policy and Management Group (EPMG), Department of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, University of London, RSM Building, Prince Consort Road, London SW7 2BP, UK. E-mail: w.sheate@ic.ac.uk Copyright  2003 John Wiley & Sons, Ltd and ERP Environment. highly politicized contexts. This paper reports on a study carried out for the European Commission to review the mechanisms of integration at strategic decision levels and to examine the role of SEA in helping to achieve better integration. This was undertaken by first reviewing integration and SEA in all EU member states and in a range of other countries and international financing organizations, and then analysing in detail 20 SEA and integration case studies at various strategic decision levels, primarily policy and plan levels. What is clear is that SEA at the most strategic level needs to be